Polyester resin composition and method for producing same

Abstract

Provided is a polyester resin composition which has a high degree of crystallinity and which crystallizes to the same degree as the surface even in the interior. A polyester resin composition comprising a dicarboxylic acid component mainly composed of furandicarboxylic acid and a diol component mainly composed of ethylene glycol, the polyester resin composition having a crystallinity of 5% or more, and the heights (I1-I4) of absorbance peaks in an infrared absorption spectrum satisfying the following formula. I1 / I2-I3 / I4 < = 0.20 (In the formula, I1 represents the height of the absorbance peak near 1340 cm <-1 > on the surface of the polyester resin composition, I2 represents the height of the absorbance peak near 1580 cm <-1 > on the surface of the polyester resin composition, I3 represents the height of the absorbance peak near 1340 cm <-1 > at a depth of 1 mm from the surface of the polyester resin composition, and I4 represents the height of the absorbance peak near 1580 cm <-1 > at a depth of 1 mm from the surface of the polyester resin composition. I4 represents the height of absorbance peak near 1580 cm-1 at a position at a depth of 1 mm from the surface of the polyester resin composition)

Description

Technical Field

[0001] The present invention relates to a polyester resin composition and a method for producing the same. Background Art

[0002] Polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) are thermoplastic resins with excellent heat resistance and mechanical properties, and are therefore used in a wide range of fields, including plastic films, electronics, energy, packaging materials, and automobiles.

[0003] However, PET and PBT are resins made from petroleum-derived substances. In recent years, from the perspective of de-petroleum, biodegradable resins and resins using raw materials derived from biomass have attracted attention as environmentally friendly or environmentally sustainable materials to replace PET and PBT.

[0004] Furandicarboxylic acid (FDCA), which is a raw material derived from biomass, has a planar structure, and therefore it is proposed that the structure is similar to terephthalic acid constituting PET.

[0005] For example, Patent Document 1 discloses a method for producing a polyester film after drying a polyester resin including a polyethylene furandicarboxylate resin under reduced pressure.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2018 / 159648 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] When polyester resin is made into a desired shape for use in various fields, the polyester resin is usually formed into a pellet shape. In addition, the pellets are usually processed into a molded body in a shape corresponding to the purpose, and the pellets are stored in a storage device such as a hopper or a tank, and are transported to a processing device such as an extruder or a molding machine through a conveying device such as a conveyor line to be processed into a molded body. However, when a pellet of a polyester resin formed of a dicarboxylic acid component with furandicarboxylic acid as a main component and a diol component with ethylene glycol as a main component is prepared and dried under reduced pressure as described in Patent Document 1, it is known that the shape of the pellet cannot be maintained due to welding during drying. As a result, it is known that the raw material input port of the conveying device and the processing device will be blocked and the supply amount will fluctuate.

[0011] An object of the present invention is to provide a polyester resin composition in which pellets are unlikely to be fused together and in which pellets are unlikely to be broken or damaged during transportation and processing.

[0012] Solutions for solving problems

[0013] The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that, although the polyester resin composition is a resin with a relatively slow crystallization rate, it has a high crystallinity and is crystallized to the same degree inside as on the surface. Therefore, when the resin composition is in the form of pellets, not only is it difficult for the pellets to be welded to each other, but the pellets are also difficult to be broken or damaged during transportation and processing, thereby completing the present invention.

[0014] That is, the present invention includes the following configurations.

[0015] [1] A polyester resin composition comprising a dicarboxylic acid component mainly composed of furandicarboxylic acid and a diol component mainly composed of ethylene glycol, wherein the polyester resin composition has a crystallinity of 5% or more and the heights I1 to I4 of the absorbance peaks in an infrared absorption spectrum satisfy the following formula.

[0016] |I1 / I2-I3 / I4|≤0.20

[0017] (wherein, I1 represents the surface 1340 cm -1 The height of the absorbance peak near 1580 cm -1 The height of the absorbance peak near the surface of the polyester resin composition is 1340 cm -1 The height of the absorbance peak near the surface of the polyester resin composition is 1580 cm-1 at a depth of 1 mm. -1 The height of the absorbance peak near . )

[0018] [2] The polyester resin composition according to [1] above, which has a crystallinity of 10% or more.

[0019] [3] The polyester resin composition according to [1] or [2], wherein I3 / I4 is 0.50 or more.

[0020] [4] The polyester resin composition according to any one of [1] to [3] above, wherein the heat of fusion ΔHm is 5 J / g or more.

[0021] [5] A method for producing a polyester resin composition, wherein the polyester resin composition is formed from a dicarboxylic acid component with furandicarboxylic acid as a main component and a diol component with ethylene glycol as a main component, wherein the polyester resin material and an inert gas in a supercritical state coexist and heat-treat the composition at a crystallization temperature of -70°C to a crystallization temperature of +10°C.

[0022] [6] The production method according to [5], wherein, following the heat treatment, the gas pressure in the supercritical state is reduced to atmospheric pressure, and the time required for the reduction is 0.5 to 20 minutes.

[0023] [7] The production method according to [5] or [6], wherein the heights I1 to I4 of the absorbance peaks in the infrared absorption spectrum of the polyester resin composition satisfy the following formula.

[0024] |I1 / I2-I3 / I4|≤0.20

[0025] (wherein, I1 represents the surface 1340 cm -1 The height of the absorbance peak near 1580 cm -1 The height of the absorbance peak near the surface of the polyester resin composition is 1340 cm -1 The height of the absorbance peak near the surface of the polyester resin composition is 1580 cm-1 at a depth of 1 mm. -1 The height of the absorbance peak near . )

[0026] [8] The production method according to any one of [5] to [7], wherein the polyester resin composition has a crystallinity of 5% or more.

[0027] [9] The production method according to [7] or [8], wherein the I3 / I4 is greater than 0.50.

[0028]

[10] The production method according to any one of [5] to [9], wherein the heat of fusion ΔHm of the polyester resin composition is 5 J / g or more.

[0029] Effects of the Invention

[0030] In the present invention, although the resin composition has a slow crystallization rate, a resin composition having improved crystallinity and crystallized to the same degree as the surface can be obtained. When such a resin composition is in the shape of pellets, not only is it difficult for the pellets to be welded to each other, but also it is difficult for the pellets to be broken or damaged during transportation and processing, so it can be suitable for a variety of industrial uses. DETAILED DESCRIPTION

[0031] [Constitution of polyester resin composition]

[0032] From the viewpoint of being an environmentally friendly or environmentally sustainable material, the polyester resin composition of the present invention is formed by a dicarboxylic acid component with furandicarboxylic acid as the main component and a diol component with ethylene glycol as the main component. "Mainly" means that in 100 mol% of the total dicarboxylic acid components, furandicarboxylic acid is 80 mol% or more, and in 100 mol% of the total diol components, ethylene glycol is 80 mol% or more. In 100 mol% of the total dicarboxylic acid components, furandicarboxylic acid is preferably 90 mol% or more, more preferably 95 mol% or more, further preferably 98 mol% or more, and particularly preferably 99 mol% or more. In 100 mol% of the total diol components, ethylene glycol is preferably 90 mol% or more, more preferably 95 mol% or more, further preferably 98 mol% or more, and particularly preferably 99 mol% or more. It should be noted that the polyester resin is a resin obtained by polycondensing a dicarboxylic acid component and a diol component, and "100 mol% of dicarboxylic acid components" means that the total amount of all units derived from dicarboxylic acids in the polyester resin composition is set to 100 mol%. The same also applies to the diol component, polycarboxylic acid component, polyol component, etc. described below, and the total amount of all units derived from these components in the polyester resin composition is taken as 100 mol%.

[0033] The polyester resin composition of the present invention may contain units derived from a dicarboxylic acid component other than furandicarboxylic acid and units derived from a diol component other than ethylene glycol, within a range not hindering the object of the present invention.

[0034] Examples of dicarboxylic acids other than furandicarboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, 4,4'-dicarboxybiphenyl, and 5-sodium sulfoisophthalic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornene dicarboxylic acid, and tetrahydrophthalic acid; and aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, octadecanedioic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, and dimer acid. Of the total dicarboxylic acid components (100 mol%), the dicarboxylic acid components other than furandicarboxylic acid are 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less, further preferably 2 mol% or less, and particularly preferably 1 mol% or less. In addition, when two or more dicarboxylic acids other than furandicarboxylic acid are used, the total amount thereof is preferably within the above range.

[0035] In addition, as a polycarboxylic acid other than dicarboxylic acid, if it is a small amount, a trivalent or higher polycarboxylic acid or hydroxycarboxylic acid may also be used in combination. As the polycarboxylic acid, ethane tricarboxylic acid, propane tricarboxylic acid, butane tetracarboxylic acid, pyromellitic acid, trimellitic acid, trimellitic acid and 3,4,3',4'-biphenyltetracarboxylic acid can be cited. In the polyester resin composition of the present invention, relative to 100 mol% of all polycarboxylic acid components, the trivalent or higher polycarboxylic acid is preferably 10 mol% or less, more preferably 5 mol% or less, further preferably 2 mol% or less, and particularly preferably 0 mol% (not containing a trivalent or higher polycarboxylic acid). It should be noted that when using two or more trivalent or higher polycarboxylic acids, their total is preferably within the above range.

[0036] Examples of hydroxycarboxylic acids include lactic acid, citric acid, malic acid, tartaric acid, glycolic acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and 4-hydroxycyclohexanecarboxylic acid. In the polyester resin composition of the present invention, the hydroxycarboxylic acid is preferably 10 mol% or less, more preferably 5 mol% or less, further preferably 2 mol% or less, and particularly preferably 0 mol% (excluding hydroxycarboxylic acid) relative to the total polycarboxylic acid components. It should be noted that when two or more hydroxycarboxylic acids are used, their total is preferably within the above range.

[0037] It should be noted that in this specification, "acid-derived units" include not only units derived from the acid but also units derived from ester-forming derivatives of the acid. Examples of ester-forming derivatives of polycarboxylic acids or hydroxycarboxylic acids include their alkyl esters, acid chlorides, acid anhydrides, and the like.

[0038] Examples of the diol other than ethylene glycol include aliphatic diols such as 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2-methyl-1,3-propylene glycol, 2-amino-2-ethyl-1,3-propylene glycol, 2-amino-2-methyl-1,3-propylene glycol, 1,10-decanediol, dihydroxymethyltricyclodecane, diethylene glycol, and triethylene glycol; ethylene oxide adducts or propylene oxide adducts of bisphenol A, bisphenol S, bisphenol C, bisphenol Z, bisphenol AP, and 4,4'-biphenol; alicyclic diols such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol; polyethylene glycol; polypropylene glycol, and the like. Of the total diol components 100 mol%, the diol components other than ethylene glycol are 20 mol% or less, preferably 10 mol% or less, more preferably 5 mol% or less, further preferably 2 mol% or less, and particularly preferably 1 mol% or less. It should be noted that when two or more diols other than ethylene glycol are used, their total is preferably within the above range.

[0039] In addition, as a polyol other than diol, if it is a small amount, a trivalent or higher polyol can also be used in combination. As a trivalent or higher polyol, trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol and hexanetriol can be cited. In the polyester resin composition of the present invention, relative to 100 mol% of all polyol components, the trivalent or higher polyol is preferably 10 mol% or less, more preferably 5 mol% or less, further preferably 2 mol% or less, and particularly preferably 0 mol% (excluding trivalent or higher polyol). It should be noted that when using two or more trivalent or higher polyols, their total is preferably within the above range.

[0040] As described above, the amount of trivalent or higher polycarboxylic acid and hydroxycarboxylic acid is preferably small, and therefore, in 100 mol% of the total polycarboxylic acid components, furandicarboxylic acid is preferably 80 mol% or more, more preferably 90 mol% or more, further preferably 95 mol% or more, particularly preferably 98 mol% or more, and most preferably 99 mol% or more. In addition, as described above, the amount of trivalent or higher polyols is preferably small, and therefore, in 100 mol% of the total polyol components, ethylene glycol is preferably 80 mol% or more, more preferably 90 mol% or more, further preferably 95 mol% or more, particularly preferably 98 mol% or more, and most preferably 99 mol% or more.

[0041] As the resin component of the polyester resin composition of the present invention, other resins such as polyamide, polystyrene, and polyolefin may be included. From the viewpoint of mechanical properties and heat resistance, the content of the resin other than polyester is preferably 20 mol% or less, more preferably 10 mol% or less, further preferably 5 mol% or less, further preferably 2 mol% or less, and most preferably 1 mol% or less relative to the polyester resin composition. It should be noted that in this specification, when a resin other than polyester is included, it is also referred to as a "polyester resin composition".

[0042] The content of the ethylene furandicarboxylate unit in 100 mol% of all structural units of the polyester resin composition of the present invention is preferably 80 mol% or more, more preferably 90 mol% or more, further preferably 95 mol% or more, particularly preferably 98 mol% or more, and most preferably 99 mol% or more.

[0043] The polyester resin composition of the present invention may contain additives within the scope that does not hinder the purpose of the present invention. Among the additives that can be used in the present invention, inactive particles such as microparticles, heat-resistant polymer particles, cross-linked polymer particles, fluorescent whitening agents, UV blockers, infrared absorbing pigments, heat stabilizers, surfactants, antioxidants, etc. can be cited according to the purpose of use. The additives may be one type or two or more types. The content of the added amount is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2% by mass or less, and particularly preferably 1% by mass or less relative to the polyester resin composition. It should be noted that when two or more addition amounts are used, their total is preferably within the above range.

[0044] As the above-mentioned fine particles, any fine particles can be selected, for example, inorganic particles such as silicon dioxide, calcium carbonate, barium sulfate, calcium sulfate, aluminum oxide, kaolinite, talc, and other organic particles can be cited. In particular, from the viewpoint of transparency, silicon dioxide particles having a refractive index close to that of the polyester resin are preferred, and amorphous silicon dioxide particles are more preferred.

[0045] The average particle size of the microparticles is preferably 1 to 10 μm, more preferably 1.5 to 7 μm, and further preferably 2 to 5 μm. When the average particle size of the microparticles is 1 μm or more, it is possible to impart a concavo-convex structure suitable for imparting lubricity to the surface of the resin composition, and thus it is preferred. On the other hand, when the average particle size of the microparticles is 10 μm or less, high transparency can be maintained, and thus it is preferred.

[0046] As the above-mentioned ultraviolet absorber, any ultraviolet absorber can be selected, for example, organic ultraviolet absorbers such as benzotriazole compounds and benzophenone compounds, or inorganic ultraviolet absorbers such as zinc oxide, titanium oxide, cerium oxide, etc. in the form of particles with a particle size of less than 0.2 μm, etc. can be listed. It can be selected from known substances according to the purpose of use.

[0047] As the antioxidant, any antioxidant may be selected, and examples thereof include aromatic amine-based antioxidants, phenol-based antioxidants, etc. As the stabilizer, examples thereof include phosphorus-based antioxidants such as phosphoric acid and phosphate-based antioxidants, sulfur-based antioxidants, and amine-based antioxidants.

[0048] [Physical properties of polyester resin composition]

[0049] The heights I1 to I4 of the absorbance peaks in the infrared absorption spectrum of the polyester resin composition of the present invention satisfy the following formula: I1 / I2 and I3 / I4 are values ​​obtained by rounding off the third decimal place.

[0050] |I1 / I2-I3 / I4|≤0.20(Formula 1)

[0051] (In Formula 1, I1 represents the surface 1340 cm-1 The height of the absorbance peak near 1580 cm -1 The height of the absorbance peak near the surface of the polyester resin composition of the present invention is 1340 cm -1 The height of the absorbance peak near the surface of the polyester resin composition of the present invention is 1580 cm -1 The height of the absorbance peak near . )

[0052] It should be noted that, hereinafter, the surface of the polyester resin composition is referred to as "surface", the position at a depth of 1 mm from the surface of the polyester resin composition is referred to as "interior", and the value on the left side of the above formula 1 is referred to as "crystallization uniformity". The crystallization uniformity of the polyester resin composition of the present invention is less than 0.20, preferably less than 0.10, more preferably less than 0.05, and further preferably less than 0.03. When the crystallization uniformity exceeds 0.20, a large difference occurs between the crystallinity of the surface and the crystallinity of the interior, and damage such as cracks and defects is likely to occur during the transportation and processing of the resin composition. The determination method of I1 to I4 is described later. The lower limit of the crystallization uniformity is not particularly limited and can be 0.00 (I1 / I2 and I3 / I4 are the same value).

[0053] I1 / I2 is preferably 0.65 or more, more preferably 0.70 or more, further preferably 0.75 or more, and particularly preferably 0.80 or more. The upper limit of I1 / I2 is not particularly limited, and is, for example, 0.90 or less.

[0054] I3 / I4 is preferably 0.50 or more, more preferably 0.60 or more, further preferably 0.65 or more, further preferably 0.70 or more, particularly preferably 0.75 or more, and most preferably 0.80 or more. The upper limit of I3 / I4 is not particularly limited, and is, for example, 0.90 or less.

[0055] From the viewpoint of making the crystallinity of the surface and the crystallinity of the interior the same degree, the polyester resin composition is preferably a pellet. The distance from the deepest part to the surface of the pellet is preferably 2.5 mm or less, more preferably 2 mm or less, further preferably 1.5 mm or less, and particularly preferably 1.2 mm or less. It should be noted that the deepest part refers to the part farthest from the surface of the pellet. For example, if it is a cylindrical pellet with a length of 3 mm and a diameter of 2 mm, the distance from the deepest part to the surface is 1 mm, and if it is a cylindrical pellet with a length of 1 mm and a diameter of 2 mm, the distance from the deepest part to the surface is 0.5 mm. As the shape of the pellet, for example, cylindrical, disc-shaped, elliptical cylindrical, elliptical disc-shaped, go-shaped, spherical, indefinite shape, etc. can be listed. From the viewpoint of productivity and processing during molding, cylindrical is preferred. In the case of cylindrical pellets, the diameter is preferably 1 to 5 mm, more preferably 1.5 to 3 mm, and the length is preferably 1 to 10 mm, more preferably 2 to 5 mm.

[0056] The crystallinity of the polyester resin composition of the present invention is 5% or more, preferably 10% or more, more preferably 10 to 50%, further preferably 15 to 40%, particularly preferably 20 to 35%, and most preferably 22 to 30%. If the crystallinity is less than 5%, more cracks, defects and other damages may occur during transportation and processing, and when pellets are made, the pellets may be fused to each other. In addition, when the crystallinity is high, the heat resistance of the polyester resin composition becomes high, so it is preferred, but from the viewpoint of the molecular structure, about 50% is the upper limit.

[0057] Regarding the crystallinity, the melting heat ΔHm (J / g) and the cold crystallization heat ΔHc (J / g) were measured, and the crystallinity Xc (%) was calculated from the following formula 2. It should be noted that the complete crystallization melting heat ΔHm 0 The value of (J / g) was set to 137 J / g as described in Physical Chemistry Chemical Physics, Vol. 16, (English), 2014, p. 7946-7958. The method for measuring the heat of fusion ΔHm and the heat of cold crystallization ΔHc will be described later.

[0058] Xc=100×(ΔHm-ΔHc) / ΔHm 0 (Formula 2)

[0059] From the viewpoint of improving the crystallinity, the melting heat ΔHm is preferably 5 J / g or more, more preferably 10 J / g or more, 12 J / g or more, 15 J / g or more, 18 J / g or more, 20 J / g or more, 22 J / g or more, 25 J / g or more, 27 J / g or more, and most preferably 30 J / g or more. The upper limit of the melting heat ΔHm is not particularly limited, for example, 60 J / g or less. When the melting heat ΔHm is less than 5 J / g, when the resin composition is made into a pellet shape, the pellets may be fused to each other.

[0060] The heat of cold crystallization ΔHc is preferably 3 J / g or less, more preferably 2 J / g or less, further preferably 1 J / g or less, and particularly preferably 0 J / g.

[0061] The apparent density of the polyester resin composition of the present invention is preferably 0.8 g / cm 3 More preferably, 1.0 g / cm 3 More preferably, 1.2 g / cm 3 Above, particularly preferably 1.4 g / cm 3 If the apparent density is less than 0.8g / cm 3 , there are many voids in the polyester resin composition, so it is possible that a large number of cracks, defects and other damages will occur during the transportation and processing of the resin composition. The upper limit of the apparent density is not particularly limited, for example, 2.0 g / cm 3 the following.

[0062] Among 10 pellets in the shape of a cylinder having a length of about 3 mm and a diameter of about 2 mm formed from the polyester resin composition of the present invention, the number of pellets having a shape retention rate of 80% or more after the impact resistance test is preferably 5 or more, and more preferably 7 or more. It should be noted that the details of the impact resistance test will be described later.

[0063] The intrinsic viscosity of the polyester resin composition of the present invention is preferably 0.3 to 1.2 dl / g, more preferably 0.4 to 1.0 dl / g or less, and further preferably 0.5 to 0.8 dl / g or less. When the intrinsic viscosity is lower than 0.3 dl / g, the resin composition becomes brittle, and a large number of cracks, defects and other damages may occur during the transportation and processing of the resin composition. On the other hand, if the intrinsic viscosity is higher than 1.2 dl / g, the filter pressure rises during melt processing, making it difficult to perform high-precision filtration, and it may be difficult to extrude the resin through the filter. In addition, when the intrinsic viscosity is higher than 1.2 dl / g, the effect of improving the mechanical properties of the resin composition may be saturated.

[0064] The moisture content of the polyester resin composition of the present invention is preferably 200 ppm or less, more preferably 100 ppm or less. If the moisture content exceeds 200 ppm, when the resin composition is made into a pellet shape, in the process of processing the pellet into a molded body, the polymer may be decomposed or the polymer discharge amount may change greatly due to pressure fluctuations. There is no particular limitation on the method for making the moisture content of the polyester resin composition of the present invention within the above range, for example, drying at room temperature or using hot air drying. The lower the moisture content, the more the decomposition of the resin is suppressed, so it is preferred, but the actual lower limit is 1 ppm. In addition, in the embodiments and comparative examples described later, the moisture content is all below 100 ppm.

[0065] The crystallization temperature of the polyester resin composition of the present invention is preferably 150 to 180° C., more preferably 160 to 175° C. When the crystallization temperature is 150° C. or higher, the crystallinity of the resin composition is easily increased, and the heat resistance is excellent. On the other hand, when the crystallization temperature is 180° C. or lower, the crystallinity of the surface and the inside of the resin composition is easily uniform.

[0066] It should be noted that the intrinsic viscosity and the crystallization temperature are values ​​inherent to the resin composition, and are physical properties that hardly change before and after the crystallization treatment described below.

[0067] [Method for producing polyester resin composition]

[0068] The method for producing the polyester resin composition of the present invention will be described, but the method is not limited to the following method.

[0069] There are no particular restrictions on the method for producing the polyester resin composition. For example, any method such as a direct esterification method in which furandicarboxylic acid is directly reacted with ethylene glycol and other dicarboxylic acid components, diol components, etc. as required, or an ester exchange method in which dimethyl ester of furandicarboxylic acid (including methyl ester of other dicarboxylic acids, etc. as required) is ester exchanged with ethylene glycol (including other diol components, etc. as required) can be used. When the moisture content of the obtained polyester resin composition is high, it is preferably dried at room temperature or dried using hot air in order to reduce the moisture content. It should be noted that commercially available products can be used as the polyester resin composition.

[0070] Next, the polyester resin composition is subjected to a crystallization treatment. Specifically, the polyester resin composition is subjected to a heat treatment in the presence of an inert gas in a supercritical state, and then the pressure is reduced from the gas pressure in the supercritical state to atmospheric pressure, thereby obtaining the polyester resin composition of the present invention. Hereinafter, the polyester resin composition before the crystallization treatment (before the heat treatment) is described as a "polyester resin material" and is distinguished from the polyester resin composition after the crystallization treatment (the polyester resin composition of the present invention).

[0071] Since the inert gas dissolves in the polyester resin material and plasticizes it, the crystallization behavior in the treatment with the inert gas under high pressure is different from the crystallization behavior under normal atmospheric pressure. Therefore, the heat treatment temperature is preferably a crystallization temperature of -70°C to a crystallization temperature of +10°C, more preferably a crystallization temperature of -60°C to a crystallization temperature, further preferably a crystallization temperature of -35°C or more and a crystallization temperature of -5°C or less, particularly preferably a crystallization temperature of -30°C or more and a crystallization temperature of -10°C or less, and most preferably a crystallization temperature of -25°C or more and a crystallization temperature of -15°C or less. The method for measuring the crystallization temperature will be described later.

[0072] The inert gas is not particularly limited as long as it is a gas that does not activate the polyester resin material, and examples thereof include oxygen, methane, propane, nitrogen dioxide, nitrogen, argon, helium, carbon dioxide, etc., among which carbon dioxide is preferably used. It should be noted that carbon dioxide may not be used as an inert gas due to reactions depending on the compound, but in this specification, "inert gas" refers to a gas that does not activate the polyester resin composition.

[0073] When the pressure during heat treatment is high, the inert gas dissolves in the polyester resin material and plasticizes, resulting in crystallization in a short time. Therefore, the pressure during heat treatment is preferably 5MPa or more, more preferably 8Ma or more, further preferably 10Ma or more, particularly preferably 15Ma or more, and most preferably 18Ma or more. The upper limit of the pressure during heat treatment is not particularly limited, for example, 50MPa. A reaction vessel that can withstand a pressure exceeding 50MPa requires a very thick metal thickness, which is unrealistic.

[0074] In order to make the pressure during the heat treatment higher than the atmospheric pressure, for example, the polyester resin material is placed in a high-pressure reaction container and connected to a gas cylinder, a pump, a pressure relief valve, a pressure gauge, a safety valve, etc. A method can be cited in which the high-pressure reaction container is heated to a predetermined temperature, an inert gas is pumped through a pump, and the pressure is adjusted to a predetermined pressure using a pressure relief valve.

[0075] The heat treatment temperature of the polyester resin composition of the present invention is preferably 105 to 180° C., more preferably 135 to 165° C. When the heat treatment temperature is 105° C. or higher, the crystallinity of the resin composition is easily increased, and the heat resistance is excellent. On the other hand, when the heat treatment temperature is 180° C. or lower, the crystallinity of the surface and the inside of the resin composition is easily uniform.

[0076] The heat treatment time is preferably 10 minutes or more, more preferably 15 minutes or more, further preferably 20 minutes or more, and particularly preferably 25 minutes or more. If the heat treatment time is 10 minutes or more, the inert gas can be fully dissolved in the polyester resin material. The upper limit of the heat treatment time is not particularly limited, for example, 200 minutes or less, preferably 180 minutes or less, and more preferably 150 minutes or less. When it exceeds 200 minutes, the effect of improving the crystallinity is saturated.

[0077] The time required for reducing the pressure from the gas pressure in the supercritical state to the atmospheric pressure is preferably 0.5 to 20 minutes, more preferably 1.5 to 10 minutes, and even more preferably 3 to 5 minutes.

[0078] The decompression rate from the gas pressure in the supercritical state to the atmospheric pressure is preferably 1 to 30 MPa / min, more preferably 2 to 25 MPa / min, further preferably 3 to 15 MPa / min, particularly preferably 4 to 10 MPa / min, and most preferably 5 to 7 MPa / min.

[0079] This application claims the benefit of priority based on Japanese Patent Application No. 2022-161069 and Japanese Patent Application No. 2022-161070 filed on October 5, 2022. The entire contents of the specifications of Japanese Patent Application No. 2022-161069 and Japanese Patent Application No. 2022-161070 filed on October 5, 2022 are incorporated herein by reference in their entirety.

[0080] Example

[0081] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples. It should be noted that the evaluation methods used in the examples and comparative examples are as follows.

[0082] (1) Intrinsic viscosity

[0083] The polyester resin material is crushed and dried. Then, the polyester resin is dissolved in a mixed solvent of p-chlorophenol / tetrachloroethane = 75 / 25 (mass ratio) in a concentration of 0.4 g / dl to obtain a solution. The flow time of the solution and the flow time of the mixed solvent are measured using an Ubbelohde viscometer, and the intrinsic viscosity of the polyester resin is calculated using the Huggins formula from their time ratio. It should be noted that the intrinsic viscosity of the polyester resin is calculated assuming that the Huggins constant is 0.38.

[0084] (2) Melting point, glass transition temperature, crystallization temperature

[0085] The melting point, glass transition temperature and crystallization temperature of the polyester resin material were measured using DSC6200 manufactured by Seiko Instruments.

[0086] (3) Melting heat ΔHm, cold crystallization heat ΔHc, crystallinity Xc

[0087] Using DSC6200 manufactured by Seiko Instruments, the temperature was raised from 25°C to 300°C in a nitrogen atmosphere at a heating rate of 10°C / min to determine the heat of melting ΔHm (J / g) and heat of cold crystallization ΔHc (J / g) of the pellets during the heating process. 0 The value of (J / g) is 137 J / g as described above, and the crystallinity Xc (%) is calculated by the following formula. Then, the average value of the heat of fusion ΔHm of the three pellets is calculated as the heat of fusion ΔHm of the resin composition, and the average values ​​of the cold crystallization heat ΔHc and the crystallinity Xc are calculated in the same manner. It should be noted that, as the pellets, except for Comparative Example 3, the pellets (polyester resin composition) after crystallization treatment are used, and the measurements after (4) are also the same.

[0088] Xc=100×(ΔHm-ΔHc) / ΔHm 0

[0089] (4) Crystallization uniformity

[0090] The Fourier transform infrared absorption spectroscopy (FT-IR) ATR (attenuated total reflection) method was used to measure the -1 The absorption of CH2 (trans structure) of ethylene glycol based on the angle-variable vibration and the absorption at 1580 cm -1 The crystallinity at the surface or at a depth of 1 mm from the surface is numerically expressed by the absorption due to the small change in crystallinity caused by the furan ring appearing near the surface. Specifically, the heights I1 to I4 of the absorbance peaks of the polyester resin composition are measured, and the difference between I1 / I2 and I3 / I4 (|I1 / I2-I3 / I4|) is calculated.

[0091] I1: 1340cm on the pellet surface -1 The height of the absorbance peak near

[0092] I2: 1580cm on the surface of the pellet -1 The height of the absorbance peak near

[0093] I3: 1340 cm at a depth of 1 mm from the surface of the pellet -1 The height of the absorbance peak near

[0094] I4: 1580cm at a depth of 1mm from the surface of the pellet -1 The height of the absorbance peak near

[0095] FT-IR ATR measurement was performed under the following conditions.

[0096] FT-IR device: Cary 660 FTIR manufactured by Agilent Technologies

[0097] 1st reflection ATR (total reflection measurement) Accessory: Specac MKII Golden Gate

[0098] Internal reflective element: Diamond

[0099] Angle of incidence: 45°

[0100] Resolution: 4cm -1

[0101] Total times: 32 times

[0102] (5) Impact resistance test

[0103] A crushing rod and a sample were placed in a polycarbonate tube of 70 mm in length and 20 mm in diameter, and the container was closed with a stainless steel lid and oscillated 150 times. A stainless steel cylinder of about 50 mm in length and 10 mm in diameter was placed as a crushing rod, and pellets of about 3 mm in length and 2 mm in diameter obtained in 10 embodiments and comparative examples were placed as samples. The pellets were taken out after vibration, and the shape retention rate of each pellet was calculated using the following formula, and the impact resistance was evaluated by the following indicators.

[0104] A: There are 7 or more pellets with a shape retention rate of 80% or more

[0105] B: 5 to 6 pellets with a shape retention rate of 80% or more

[0106] C: The number of pellets with a shape retention rate of 80% or more is 4 or less

[0107] Resin pellet shape maintenance rate (%) = volume of pellets after shaking ÷ volume of pellets before shaking × 100

[0108] (6) Apparent density

[0109] The mass and volume of the pellets were measured, and the apparent density was calculated using the following formula: The apparent density was calculated using 10 pellets, and the average of the apparent densities of 8 pellets excluding the upper limit and the lower limit was taken as the apparent density of the resin composition.

[0110] Apparent density (g / cm 3 ) = mass (g) / volume (cm3 )

[0111] (7) Welding

[0112] 5 g of the pellets were placed in a 10 mL glass vial, and heat-treated at 120° C. for 1 hour in a nitrogen atmosphere. The pellets were then cooled to room temperature and taken out, and weldability was evaluated using the following indices.

[0113] A: The pellets are not welded together and can be taken out one by one

[0114] B: Slight fusion of the pellets was observed, but the pellets could be easily separated and taken out one by one.

[0115] C: The pellets are found to be welded together and it is impossible to remove the pellets one by one

[0116] (Example 1)

[0117] A polyester resin material in the form of cylindrical pellets having a length of about 3 mm and a diameter of about 2 mm was prepared by the following production method.

[0118] 149 ppm of tetraethylammonium hydroxide (calculated as molar ppm of N(Et)4OH based on the molar amount of FDCA) was added to the starting mixture of 2,5-furandicarboxylic acid (FDCA) and ethylene glycol (EG) (the molar ratio of EG / FDCA was 1.5). Next, the temperature of the mixture was slowly raised from 80°C to 220°C while esterification was carried out for 3.2 hours. After volatile compounds such as water were distilled off, a polycondensation catalyst and a phosphorus compound were added. It should be noted that an ethylene glycol solution of basic aluminum acetate was added as a polycondensation catalyst, and an ethylene glycol solution of diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate was added as a phosphorus compound. The ethylene glycol solution of basic aluminum acetate and the ethylene glycol solution of diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate were added in such a manner that the amount of aluminum was 202 ppm and the amount of diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate was 435 ppm relative to the molar amount of FDCA in the starting mixture. The temperature of the mixed solution to which the ethylene glycol solution was added was raised from 220°C to 270°C, and the pressure was reduced to 1 mmHg (about 133 Pa) to carry out the initial polycondensation for 60 minutes. Furthermore, the post-polycondensation was carried out at about 13 Pa and 270°C for 119 minutes. At the end of the polycondensation, the pressure was set to normal pressure, and the polycondensate was passed through water in the form of a strand and cooled, and then cut to obtain a pellet in the shape of a cylinder with a length of about 3 mm and a diameter of about 2 mm, i.e., a polyester resin material.

[0119] The above-mentioned polyester resin material is a polymer formed by units derived from furandicarboxylic acid components, units derived from ethylene glycol components, and units derived from diethylene glycol components (4.0 mol% relative to all units derived from diol components), the content of aluminum atoms derived from the catalyst component is 30 ppm, the content of phosphorus atoms derived from the catalyst promoter component is 74 ppm, the intrinsic viscosity is 0.62 dL / g, the crystallization temperature is 170°C, the melting point is 215°C, the glass transition temperature is 86°C, and the crystallinity is 3%.

[0120] After the obtained polyester resin material was dried under reduced pressure (1Torr) at 80°C for 12 hours, 4 g was weighed and put into a 10 mL reaction container. It should be noted that at the time of the above-mentioned input, the reaction container was preheated to a temperature close to 150°C. Carbon dioxide was delivered to the reaction container at a flow rate of 5 mL / min from a pump connected to the carbon dioxide bottle, and the pressure in the reaction container was adjusted to 20 MPa after 3 minutes with a pressure relief valve, and then crystallization treatment was carried out at 150°C for 30 minutes. After the crystallization treatment, the pressure in the reaction container was reduced to atmospheric pressure at a pressure reduction rate of 5 MPa / min to obtain a polyester resin composition. The polyester resin composition was taken out of the reaction container without cooling the container, and the physical properties were evaluated after cooling to room temperature. The evaluation results are shown in Table 1.

[0121] (Examples 2 to 9)

[0122] A polyester resin composition was obtained in the same manner as in Example 1 except that the treatment conditions were changed as shown in Table 1. Table 1 shows the evaluation results.

[0123] (Comparative Example 1)

[0124] The polyester resin material obtained by the manufacturing method described in Example 1 was dried under reduced pressure (1 Torr) at 80°C for 12 hours, 4 g was weighed, and put into a 10 mL reaction container. The reaction container was filled with air and the pressure was atmospheric pressure. Then, the reaction container was heated to 150°C and crystallized for 180 minutes to obtain a polyester resin composition. The polyester resin composition was taken out from the reaction container and evaluated for physical properties. The evaluation results are shown in Table 1.

[0125] (Comparative Example 2)

[0126] The evaluation results are shown in Table 1.

[0127] (Comparative Example 3)

[0128] The polyester resin material obtained by the production method described in Example 1 was dried under reduced pressure (1 Torr) at 100° C. for 24 hours, and then its physical properties were evaluated. The evaluation results are shown in Table 1.

[0129] [Table 1]

[0130]

[0131] In Comparative Examples 1 and 2, the crystallization process was performed using air without using an inert gas, so the crystallinity of the interior was significantly inferior to that of the surface, and cracks or defects were easily generated in the pellets due to impact. It should be noted that in Comparative Examples 1 and 2, the crystallization process itself was performed without using an inert gas, so unlike Comparative Example 3, no welding occurred.

[0132] In Comparative Example 3, even if the reduced pressure drying was performed at high temperature for a long time, the crystallinity was the same as that before the reduced pressure drying, so the pellets were easily cracked and damaged by impact. In Comparative Example 3, the pellets were fused to each other.

[0133] Industrial Applicability

[0134] The polyester resin composition of the present invention has a high degree of crystallinity and is crystallized to the same extent inside as on the surface, and therefore can be suitably used in various industrial applications.

Claims

1. A polyester resin composition comprising a dicarboxylic acid component having furandicarboxylic acid as a main component and a diol component having ethylene glycol as a main component, The polyester resin composition has a crystallinity of 5% or more, And the heights I1 to I4 of the absorbance peaks in the infrared absorption spectrum satisfy the following formula: |I1 / I2-I3 / I4|≤0.20 Wherein, I1 represents the 1340 cm -1 The height of the absorbance peak near 1580 cm -1 The height of the absorbance peak near the surface of the polyester resin composition is 1340 cm-1 at a depth of 1 mm. -1 The height of the absorbance peak near the surface of the polyester resin composition is 1580 cm-1 at a depth of 1 mm. -1 The height of the absorbance peak near .

2. The polyester resin composition according to claim 1, which has a crystallinity of 10% or more.

3. The polyester resin composition according to claim 1 or 2, wherein The I3 / I4 is greater than 0.

50. 4 . The polyester resin composition according to claim 1 , which has a heat of melting ΔHm of 5 J / g or more.

5. A method for producing a polyester resin composition, wherein the polyester resin composition is formed from a dicarboxylic acid component mainly composed of furandicarboxylic acid and a diol component mainly composed of ethylene glycol, The production method is characterized in that the polyester resin material is placed in the presence of an inert gas in a supercritical state and heat-treated at a crystallization temperature of -70°C to a crystallization temperature of +10°C.

6. The manufacturing method according to claim 5, wherein: After the heat treatment, the gas pressure in the supercritical state is reduced to atmospheric pressure, and the time required for the reduction is 0.5 to 20 minutes.

7. The manufacturing method according to claim 5 or 6, wherein: The heights I1 to I4 of the absorbance peaks in the infrared absorption spectrum of the polyester resin composition satisfy the following formula: |I1 / I2-I3 / I4|≤0.20 Wherein, I1 represents the 1340 cm -1 The height of the absorbance peak near 1580 cm -1 The height of the absorbance peak near the surface of the polyester resin composition is 1340 cm-1 at a depth of 1 mm. -1 The height of the absorbance peak near the surface of the polyester resin composition is 1580 cm-1 at a depth of 1 mm. -1 The height of the absorbance peak near .

8. The manufacturing method according to claim 5 or 6, wherein: The polyester resin composition has a crystallinity of 5% or more.

9. The manufacturing method according to claim 7, wherein: The I3 / I4 is greater than 0.

50.

10. The manufacturing method according to claim 5 or 6, wherein: The polyester resin composition has a heat of fusion ΔHm of 5 J / g or more.

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